There are many different types of grips used today for a wide variety of items, including without limitation, golf clubs, tools (hammer handles, screwdrivers, etc.), racquets (racquet ball, squash, badminton, or tennis racquets), bats (baseball or softball), pool cues, umbrellas, fishing rods, etc. While particular reference for this disclosure is being made to the application of golf club grips, it should be immediately apparent that the present disclosure is applicable to other grips as well.
Slip-on golf club grips made of a molded rubber material or synthetic polymeric materials are well known and widely used in the golf industry. The term “slip-on” as employed herein refers to a grip that slides on to a shaft or handle and is secured by way of an adhesive, tape, or the like. Slip-on grips are available in many designs, shapes, and forms.
Golf club grips historically have been made of a wide variety of materials such as leather wrapped directly on the handle or leather wrapped on sleeves or underlistings that are slipped on to the handle, or more recently rubber, polyurethane or other synthetic materials are used. Efforts to date have largely focused on reducing the vibrations transmitted from the shaft to the golf grip. Such reduced vibration transmission also reduces the feel of a golf club and does not provide the golfer with sufficiently accurate tactile feedback, which is particularly true for a putter. The golfer may describe the lack of feedback as producing a hollow, muffled, or disconnected feeling.
Up until now, various construction methods have been used to produce a lower overall material density. Most commonly, an inner structure is formed using a light weight foam material, often EVA foam. Over this structure, a gripping layer is located and held in place through the use of either an adhesive or some other bonding method. Most commonly, this gripping layer is made from a felt material where the outside is coated in polyurethane to provide a smoother and more durable outer layer.
The limitations of this construction is that there is lower vibration transmission through a putter grip of this variety versus a standard sized grip of traditional construction, primarily due to the construction, materials utilized, and method of manufacture. There are a number of issues related to the lower vibration transmission, however an important one is associated with the amount of vibration which reaches the hands of the user (golfer) during the act of putting a golf ball. Putting is a relatively low energy event and any loss of vibration transmission will result in the feel of impact being deadened. This deadening of impact causes the user to have less indication of how well they impacted the ball and greatly reduces the “feel.” Golfers use this “feel” as feedback to be able to improve the quality of their ball impact, thus the existing grips actually remove some of the golfers' ability to improve. Golfers describe this experience as being “isolated” or “detached” and this makes it very difficult to know if a certain action, or impact, has been repeated or not. Additionally, the “feel” of golf ball impact is, to some golfers, part of the enjoyment of playing golf and, by removing this “feel”, the level of enjoyment may be reduced.
Another existing method of manufacturing a lightweight structure to form a grip is to use expanded foam/sponge material tubes (EVA, nitrile rubber, etc.) and grind them to shape. The material properties of these tubes are such that they are sold for their vibration reducing properties and therefore have the same issue as the aforementioned grips. These foam/sponges also have relatively low abrasion and UV resistance, and tend to wear out more quickly than traditional rubber grips.
Thus, there still exists a need for a hand grip that preferentially promotes transmission of vibration through the structure to the human hands holding the grip, particularly a grip that efficiently transmits vibrations in the frequency spectrum within which human hands are most sensitive.